Clutch



Patented July 5, 1932- Ti PM D ooixnann LOUIS PFEIFFER, or GHIGAGOLILLINOIS. ASSIGNOR T WESTERN ELECTRIC COMPANY, INCORPORATED, 0F YORK, 1\l Y., CORPORATION 'OF NEW YQRK' CLUTCH 3' Application filed May 24,

This invention relates to clutches, and more particularly to an alternating current mag netic clutch. v P v v The primary object of the present invention is to provide a simple and durable elecof laminated magnetic material having slots in which are mounted polyphasewindings connected to a source of electric current. Constantly rotatingfiux of one or more pairs of poles produced by the current within the windings effects the attraction of a laminated armature attached to a shaft carrying one disk of a friction'clutch.

Itis believed that a complete understand- 29 ing of the invention may be had byreference to the following description takenin conjunction with the accompanying drawing. illustrating a device embodying the invention, and in which,

Fig. 1 is a front elevational view'of the clutch, the upper half of the electrical actuating portion thereof being shown in longi'-' tudinal section;

Fig. 2 1s a SGCtlOIlEtl vlew taken on line 2-2 19 of Fig. 1 illustrating the manner in which the stator is laminated and provided with polyphase electrical windings, and

F1g. 3 1s a dlagrammatlc representatlonof the winding connections.

Referring now to the drawing wherein like numerals'have been employed to designate similar parts throughout the various figures, it will be observed that astator denoted gen erally by the numeral 10 is rigidly supported 1 within an annular bracket 11 composed .of

any suitable non-magnetic material and fastened to a frame 12 secured to a base 13. The

stator 10 comprises a thin silicon steel ribbon 18 wound into a ring 19 of electrically insulated layers and retained by any suitable means (not shown) within an annular recess 20 provided in the bracket 11. Silicon steel is used on account of its. extremely low hys-. teresis and eddy current losses, which losses are further decreased by oxidizing the surface 1928. Serial No. 286,199.

of the silicon steel. The laminated ring .19 has radial slots 24 inwhich are mounted p'olyphase coil windings 25 to inclusive,as illustrated in Fig. 2 of the drawing, or the'windi ing may-be of any, other suitable type commonl'y. used in polyphase induction motors.'

"An annular laminated" armature 34 made from silicon steellribbon is mounted, on a non.-

magnetic hub 35 which is connectedthrough a thrust bearing 33t'oa shaft 36'concentric with the ring 19 and journaled withinv acolumn'37 formed as an integral part ofthe frame 12., The thrustlbearing permits the armature 34 to remain stationary or to freely rotate. .The laminated armature 34withits thin coating of insulation between each layer prevents the inducing ofeddy currents therein, and since there are no currents in thearmature -to react magnetically onthe, rotating field produced by the alternating current in the polyphase windings 25 30, there is no torque or motor actionto ,cau se'rotation of the armature. Thus, the magnetic linesof to attract the armaturebut not-to 'eflect rotation thereof. .7 7

One end of the shaft 3610 11. which is mountforce resulting from theenergizing current of the polyphase windings 2530 will be used ed the armature 34: carries a friction disk 38 which forms the driven member of the clutch contact with a companion-driving disk 39 seare. delta-connected as diagrammatically il ilus'tr'ated in Fig. 3 of the drawing through a switch 46"t'o' a source (not'shown)' of three phase alternating current. When the switch, f

&6 is closed the polyphase currents apart flow in the windingsfto produce a constant rotating;fi 'eld having" revolving north :and' v south poles which attract the armature34 thereby compressing the sprin 44. and retaining the diski38in' contact with the rotatfltflv I 8o 1 and is adapted to be brought into frictional with the electro-magnet after the energizing on the shaft =36'that when the friction disks current has been discontinued. To over come this so called freezing of the armature 34 to the stator and to avoid abrasion of their surfaces the armature 34: is so placed 3839 are in engagement there will still exist a very minutefair gap between the armature 84 and the laminated ring '19. In the operation of the clutchthe switch 46 is closed to connect the polyphas'e vr'rindin-g of the stator .10 to a source of alternating three phase current. The current within the windings 2'5-3 0' produces a constant rotating flux of north and south poles which attract the armature 34jand thereby engage the friction clutchf When the switch 46 is opened, the energizing current, which produces the alttraction or pull, is discontinued and the spring 44; then forces the friction disks 38-39 out ofengagement to stop the driving of the u l shaft 36.

- It is to be particularly noted that the invention eliminates the necessity of using slip rings or other troublesome commutating de vices, Furthermore, the clutch can be advantageously used with apparatus where only alternating current is available, thereby avoiding the expense of providingasource of direct current. g

It will be understood thatthe embodiment of theinvention herein described and il'lustrated is merely a convenient and useful form offthe invention which is capable of many otherfl'mo difications without departing from the spirit and scope of the invention as defined bv the appended claims.

i What is claimed is:

secured to the friction disk to be driven and j ournaled to permit its own slight longitudinal movement, a resilient member pressing against a shoulder of the second shaft to maintain the friction disks separated, an alternating current stator spaced from the friction disks and surrounding the second shaft, said stator having inserted in a groove thereof a ring of insulated laminations which are slotted radially at spaced points, polyphase alternating current windings secured in the radial slots, and an armature including a ring of insulated laminations freely journaled upon the second shaft but longitudinally fixed thereto and attracted by the stator to move the friction disks into engagement with each other.

3'. In an alternating current magnetic clutch, apower driven shaft, a friction disk sec-ured'to the end thereof, a second friction disk spaced o-p'p'osite the" first friction disk,

asec'ond' shaft to be driven having itsend secured to the second friction disk, means for my name this 12th day of May, A. D. 1928.

' FCONRAD LOUIS PFEEFFER.

. 1. Inan alternating current magnetic 4 clutch a di 'lvlng shaft, a frlction disk secured to its end, a friction disk positioned opposite the first friction'disk,a second shaft to theend of which said second friction disk is secured and capable ofa slight longitudinal movement, a laminated alternating current stator spaced from the friction disks and surrounding the second shaft, a laminated armature free to; rotate around the second shaft but fixed longitudinally thereon, said i armature being'positioned adjacent the stator so thatelectrical energization'of the latter moves the armature and the second shaft endwise to cause engagementof the two fric ti'on disksfto drive-the second shaft, and a resilient member for normally maintaining .9 the friction disks separated. v

2. In an.- alternating current magnetic clutch, a power driven shaft, friction disk secured to the end thereof, a friction disk.

- to be driventhereby spaced opposite said first friction disk a slight distance,a second shaft 

